If A is a matrix of order 3 and |adj A| = 7 , then the value of |A| is

\(\sqrt { 7 }\) - \(\sqrt { 7 }\) Both (a) and (b) None

Both (a) and (b)

We know that |adj A| = \( { |A| }^{ n-1 } \) , where n is the order of matrix A. So, |adj A| = \( { |A| }^{ 3-1 } \) = \( { |A| }^{ 2 } \)         7 = \( { |A| }^{ 2 } \)      |A| =   \(\sqrt { 7 }\), -\(\sqrt { 7 }\)